Apparatus for controlling thread tension in looms for weaving



R. ROSSMANN APPARATUS FOR CONTROLLING THREAD TENSION IN LoOMs FORWEAVING Filed Jan. 10, 1935 3 Sheets-Sheet l FoJJnzazzzz. M 4

A, 10, 1937., R. ROSSMANNY APPARATUS FOR CONTROLLING THREAD TENSION INLOOMS FOR WEAVING Filed Jan. 1Q, 1935 3-Sheets-Sheet 2 JIM? Jeiibruqy.

Au 10, 1937.. R. ROSSM'ANN APPARATUS FOR CONTROLLING THREAD TENSION INLOOMS FOR WEAVING Filed Jan. 10, 1955 3 Sheets-Sheet 5 72221222 forjniozfiflmzan 2;

Patented Aug. 10, 1937 PATENT OFFICE APPARATUS FOR CONTROLLING THREADTENSION IN LOOMS FOR WEAVING Rudolf Winterthur, Switzerland, as-

signor to Tefag Textil-Finanz A. G., Zurich,

Switzerland Application January 10, 1935, Serial No. 1,166

In Switzerland 8 Claims.

Thisinvention relates to a method and apparatus for controlling thetension of the weft thread in looms, particularly in looms havinggripper shuttles.

In looms operating with gripper shuttles, the conditions of and aroundthe weft thread are different from the conditions in looms operatingwith shuttles carrying thesupply of thread themselves. In the lattercase, the weft thread which 10 has left the shuttle rests stationarywithin the shed, whereas, in the former case, the weft thread-flies withconsiderable speed, namely, practically the same speed as the shuttlehas.

' through the shed. The thread, particularly if heavy and/or stiffmaterial is used, constitutes considerable mass and accumulates greatinertia during the weft so that"the thread runs after the shuttle andtoo much thread is supplied so' that means must be provided to removethe excessive amount from the shed. The massaction of the thread isaugmented by the air surrounding the weft thread and which develops aconsiderable air current during and right after the flight of theshuttle and weft thread through 5 the shed. Further, in looms havinggripper shuttles, the weft thread runs off comparatively large bobbinsalso constituting great mass and inertia. If stiff and/or heavy threadmaterial is used, too much thread may be fed into the shed at certainmoments, in other cases great resistance must be overcome in order topull the thread off the supply bobbins. It is an object of the presentinve'ntion to provide methods and apparatus which eliminate alldisadvantages which are caused by the before stated conditions. Anobject of the present invention resides in the provision of a loom forweaving in which the tension of the weft threads ispositivelycontrolled, and the shrinkage and character of the 40 fabric can bepredetermined by controlling the tension of the individual weft threads.

In looms having grippershuttles, the tension of the weft threads whichare, pulled through the Y warp, sometimes against considerablefrictional 45 resistance, is often much greater than in looms in whichthe weft thread runs off the shuttles. In such cases, gripper shuttlescould hitherto only be used for producing fabrics which permit greattension of the weft threads. The present inven- 50 tion has for itsobject to provide weft thread tension control means by which the tensionof the weft threads can be positively adjusted, and

January 17, 1934 vision of an apparatus by means of which the length ofthe weft threads in looms for weavin can be controlled either during orafter the weft, i. e., the weft thread is shortened orlengthened duringor after the passage of the gripper shuttle through the warp.

Another object of the present invention is to provide an apparatus whichassures the lengthening of the weft threads during and after the weft tosuch an extent that shrinkage of the produced fabric is eliminated.

A further object of this invention is the provision ofv a controlapparatus for adjusting the tension of the weft threads in looms forweaving, whereby the provision of special fabric stretchers is renderedunnecessary or only a gentle pull is sufficient for stretching thefabric to maintain the desired width.

Another object of the present invention is to provide a method andapparatus for adjusting the tension of the weft threads in looms forweaving, whereby a particularly tight fabric can be obtained withoutincreasing the impact of the lay whereby, on the contrary, this impactmay be reduced, and the warp threads suffer much less, and breaking ofwarp threads is substantially reduced. I

A further object of my invention resides in the provision of a methodand apparatus for controlling the tension of the weft threads in loomsfor weaving, whereby an adjustable amount of brake action is applied tothe weft threads which prevents undesired curling when using muchtwisted or crape threads and permits faultless weaving of such threads.

Other objects of the present invention will be method and apparatusaccording to the present invention and will be set forth in the claimsand the description relating to the drawings which, by way ofillustration, show what I now consider to be preferred embodiments of myinvention.

In many cases, it is sufiicient if the weft thread is lengthened only onone side of the fabric after the pick is completed. If the thread'iselastic, the elongation is instantly distributed over the whole width ofthe fabric. According to the invention, the shuttle may be allowed totravel beyond the edge of the fabric after it has passed through thewarp and then be moved back towards the fabric. In such manner, weftthreads are used which are longer by the distance which the shuttle hastraveled beyond the warp. In looms having gripper shuttles and threadfeeders for feeding the thread to the shuttles, addiapparent from thefollowing broad outline of the.

40 a y In such cases and without applying the present invention, theedge of the fabric has an arched thread is then determined by thedistance of the point where the gripper engages the thread from the edgeof the fabric. Obviously, a special gripper may be used and operatedindependently of the thread feeder.

The before described means can he applied to both sides of the fabric.The motion of the gripper located at that side from which the thread isfed into the fabric may be started just at the moment when the weftthread is still. moving due "toits own inertia, whereby the additionalsupply of thread is equally distributed over the. whole width of thefabric, also when using threadmaterial which is not elastic. Thisdistribution I will hereafter be fully equalized by the impact of thelay and'by thegpressure of the warp threads so that homogeneous textureis obtained having only very little or no shrinkage at all.

When making fabrics in which the weft threads are under great tension,it has been found that the weft thread sustains greater tension whenstretched after the pick than when applying great tension during thepick. According to the presentinvention, for such cases a special weftthread stretcher is provided outside of the shed which may be operatedby an adjustable spring and which appliesa. predetermined tension toeach weft thread after the pick. This method is particularlyadvantageouswhen the weft bobbins do not operate absolutely equally sothat the weft threads may run off more easily at certain times and lesseasily at other times.

configuration. Such faults in the fabric are completely eliminated ifthe tension of all the weft threads is equalized by the before mentionedweft thread stretcher. The effect of supplying additional weft threadand weft tension may also be combined which is of particular advantagein most cases. The weft threads are first brought to equal tension afterthe: pick in order to eliminate loops and loosening, and thensupplementary thread material of predetermined length is added so thatall weft threads have the-same length and tension.

In the drawings:

Fig. 1 is a diagrammatic part cross sectional view of a mechanism formaintaining the weft thread under a predetermined tension during thepick, slackening and/or stretching the weft thread after the pick. I t

Fig. 2 isv a diagrammatic view of part of the mechanism illustrated inFig. 1, however,'in

another phase'of operation.

Fig. 3 shows another phase of operation of the mechanism illustrated inFigs. 1 and 2.

Fig. 4 is a diagrammatic showing of the mechanism shown in Figs. 1 to3,. however. in still another phase of operation.

Fig; 5 is a modification of a detail of the mechanism shown in Figs. 1to 4.

Fig. 6 is adiagrammatic longitudinal cross sectional view of a-pneumaticthread stretcheraccording to my invention.

, Fig. 7 is a diagrammatic transverse sectional view of the threadstretcher shown in Fig. 6

and taken along line 1-1 of Fig. 6.

Fig. 8 is a diagrammatic showing of a mechanical thread stretcheraccording to my invention.

Fig. 9 is a diagrammatic showing of a thread gripper mechanism forfeeding additional thread or stretching the thread.

Fig. 10 is a diagrammatic showing of a comb type weft thread stretcheraccording to my invention.

Fig. 11 and Fig. 12 are diagrammatic cross sectional views of a layequipped with a thread stretcher according to Fig. 10 and showing thestretcher in two different phases of operation.

Fig. 13 diagrammatically shows a mechanism for feeding .in additionalweft thread after the pick, the figure showing the individual parts inthe position during the pick.

Fig. 14 shows the'same'mechanism as illustrated in Fig. 13, the movableparts being in the position after the pick.

Referring more particularly to Figs. 1 to 4 ofthe drawings, the weftthread I is pulled from bobbin it during' the pick of shuttle l. Pickingmeans are not shown as these are not part of the present invention. Theweft thread passes through the disc brake II which makes the tension ofthe thread substantially independent of the running off conditions ofthe thread off bobbin l3. Thereafter it passes the'loop 45 of thestretching device I 6. 6 indicates the warp threads forming the shed.After theshuttle has arrived at the shuttle receiving box l8 and is heldtherein by braking means which are not illustrated, the weft thread laysin the shed under equal tension which is substantially due to brake- I.By adjustment of the latter, the tension of the thread during the' pickcan be predetermined.

After the pick,the apparatus is in the position illustrated by Fig. 1.Right after the pick, jaws l9 and are closed as shown in Fig.2 and movedtowards edge 2| of the fabric into the position shown in Fig. 3. Amechanism which may be used for accomplishing this is shown separatelyin Fig. 9 and will be described later. On the other side of the fabric,shuttle l is pushed towards the fabric edge 23 by means of pusher 22(Fig. 3). This causes a slackeningof the weft thread 4 which canbeexactiy adjusted by suitable determination of the distance over whichJaws iii-'20 and shuttle-l are moved towards the center of the fabric.For smaller fabrics or fabrics of certain character, only the mechanismon one side may be used for slackening, or the jaw moving mechanism andthe shuttle moving mechanism may be used alternately or operatedaccording to a certain predeter- 'chain'hangs on chain wheel 18 which isconnected to and driven by the driving mechanism of the loom. Thisconnection is not shown as it is not part of the present invention.Whenever a link having a' projection 14 comes into the fabric edge 23and the weft thread slackened. The projections of some links may besmaller- 14and other links may not have any projections at all. Theslackening of the weft thread is in proportion to the stroke of rod I!which depends on and can be predetermined by the configuration of links1|. .By these means, various characters of fabric can be obtained. Forexample, a certain part of the weft threads are slackened and producecrimping and craping, whereas others are stretched producing repp. Byproper combination of these various characters of weaving within' thesame fabric, a great amount of varieties of patterns can be obtained.

Additional tension may be applied to the weft thread during or after thepick by the means shown adjacent to the disc brake l4. As be- I foresaid, the weft thread passes through the eye 45 of the double leverl6/52 which is revolvable around pivot 5|. 'Eye 45 extends into anopening of the loom structure having rounded rims 46 and 41. At asuitable moment, latch 50, which is revolvable around pivot 49 and holdsthe double lever against spring 53 in a position in which eye 45 extendsinto the opening, is turned clockwise by means 48 which are not shown indetail and frees double lever l6/52.

Eye 45 then snaps downwards taking the weft thread with it and pullingthe weft thread into a loop 46-4541. By proper adjustment of spring 53,the extent of movement of lever l6/52,

the size of the loop and the tension of the weft thread can bepredetermined. Disc brake I 4 takes care that no undesired thread ispulled off the bobbin i3. It is obvious that the laws if! and 20 must beopen during this action of the thread tensioner [6/52. The double leveris pulled back into starting position by means of chain 80 which isperiodically operated by cam 8 i. This cam is rotatably connected to andoperated by the loom driving mechanism. This connection is not shownbecause it is not part of the invention.

The just described thread tensioner may also be operated to act asthread slaokener and to allow a predetermined additional length of weftthread. to pass into the shed. For this purpose, lever l6 and eye 45 arenormally in the position shown in Fig. 4. At the moment when anadditional supply of weft thread is desirable, the lever is movedcounter-clockwise by the means 80 and 8 I.

Fig. shows a modification of the weft thread control described in theforegoing. paragraphs. The thread passes through the three eyes 42, 43and 44. The eye in the middle-43-is provided with an upward extension I9which is connected with one end of spring 11, the other end of which isfixed to a stationary part of the loom. Eye 43 also has a downwardextension 69 which cooperates with lever 18 which is pivoted to astationary part of the loom. Lever 78 may be connected to and operatedby a moving part of the loom. Such a connection has not been shown as itis not part of the present invention. Eye 43 can be moved downwardsagainst the tension of spring 11 by turning lever 18in counterclockwisedirection so that the thread is pulled into the loop 42-, 43', 44 shownby dotted lines.

Figs. 6 and 7 show a weft thread tensioner operated by a current of airproduced by blower II and controlled by valve 16. The channel 60 for theweft thread 4 is crossed by the air channel 6|, the end of which isflattened as is obvious from Fig. 7. During the pick, the air currentPresent ages the other side of abutment 69.

continuously maintains a tension in the weft thread which then forms asmall loop as indicated by dotted lines in Fig. 6. As soon as theshuttle is stopped, the weft thread is blown into a larger loop andtension maintained on the thread which would otherwise be loose withinthe shed and possibly curl due to its own inertia. By adjustment of theair supply to channel 6|, the tension of the thread can also beadjusted.

-. This is done by providing valve 16 in duct 6|.

Fig. 8 shows a mechanical means for maintainis limited and thereby thetension applied to the thread is controlled by the stop member 59' whichhas the shape of an eye through which the weft thread runs and isprovided withconical external surfaces facing jaws 55-56. When thesejaws, pulled by the weft thread, run against the conical part of stopmember'59, the jaws are opened and thread 4 is freed. Thereupon spring58 pulls back jaws 55-56 which then close again on the weft thread. Stopmember 59 is connected to a mechanism 3 which permits its movement inthe direction of the weft thread. Thereby the amount of tension appliedto the thread can be adjusted.

Fig. 9 shows in detail the clamps l9 and 20 already mentioned inconnection with the description of Figs. 1 to 4 and, in a schematic man,ner; a mechanism which may be used for their operation. Clamp holder 62which may be identical with the thread giver as described in my shown insolid lines, i. e., inclined to the direc- 'tion of the thread, the jawsare closed. If it is turned clockwise so that it stands perpendicular tothe thread, the jaws are spread apart and thethread is free. Thisclockwise movement is effected whenever one side of abutment 65 runsagainst the plate spring 63 attached to the end of latch 66. The lawsclose when spring 63 en- Spring 63 flexes and passes underneath abutment69 when member 62 moves to the right. At this movement, it pushes thread4 to the right with the jaws closed feeding additional weft thread tothe shed and slackening the thread. Abutment 69 is then also moved tothe right and follows member 62 until it touches spring 63 and turnslatch 66 clockwise, thereby spreading the laws apart and freeing thethread. Now member 62 can be moved to the left. While spring 63 passesabutment 69 underneath, a further clockwise movement of latch 66 isprevented by nose 64 projecting from member 62.

The mechanism for producing the reciprocating movement of abutment 69consists of rod 82 moving in bearings 83 and operated by the groove 88which is driven by the loom driving mechanism. The latter is not shownas it is not subject matter of the present invention. It is obviousthat, by suitably designing and operating cams B4 and 81, the apparatuscan be used not only for slackening the weft threads. but also forstretching the weft threads. In this case, jaws l9 and 28 are closedwhen they are farthest to the right and then pull the thread to the leftand thereby stretch the weft thread.

Figs. 10 to 12 show a mechanism for progressively applying additionalweft thread. 6 are the warp threads in section. 4 is the weft thread.After the weft, arm 29 of a plurality of bellcrank levers 28-29 engagesthe weft thread and pulls I of the bellcrank lever is shown in Fig. 11.

it downwards in between two adjacent warp threads so that loops areformed. This position The bellcrank levers'are rotatably supported byrod 21 mounted to lay 28. For accommodating arms 29 and the loops of thethread, a longitudinal groove 3| is provided inlay 26. If thelongitudinal member 33 which is provided with a plurality of inclinedcams 34 engaging arms 28 of the bellcrank levers is moved towards theleft, one

" crank lever after the other starting from the right is turnedclockwise and loops 32 are formed in the weft thread in the samesuccession. Since the right end of the weft is heldby, the shuttle andby already formed loops, additional loops to the left can only beformed'by pulling {additional thread from the bobbin which is on theleft side. After the loop forming operation is completed, cam .member 33is moved towards the right and the bellcrank levers all turncounter-clockwise into the position shown in Fig. 12 by the action ofspiral springs 30, one end of which is connected to rod 21 and the otherto arm 29. .At the then following beating up. of the weft thread, theadditional supply of weft-thread is equally distributed over thewhole'width of the fabric. If the apparatus is arranged and operated forforming the loops of the weft thread consecutively from the left sidetowards-the right side, i. e., in the direction of the movement of theshuttle, additional tension may be applied to the thread.

Figs. 13 and 14 illustrate another method of supplying additional weftthread. just at the end of the pick. A buffer member 1 is providedwithin the shuttle receiving'box 2 which is pushed to I the right by theincoming shuttle and abuts against the one arm lever 35 turning it in aclockwise direction around its fulcrum 36. The

end of lever 35 is connected by a connecting element 3'! with the end oflever 38 which rotates.

member 4| whenever lever 38 is turned clockwise. The connecting member34 moves to the right upon clockwise operation of lever 35 by theincoming shuttle and not only turns lever 38 clockwise, thereby engagingthe weft thread, but

also pulls slide member 4| to the right and there-' by pushes additionalweft thread to the right, i. e., into the shed. By adjustment of thelength of levers 35 and 38, the amount of additional thread supplied canbe definitely controlled. The starting position oflever 35 isdeterminedby the position of the adjustment screw 15 against which lever35 abuts whilethe shuttle is on the way. Slide member 4| and levers35and 38 may be pulled backwards into starting position by a mechanismindicated by the string 24, the roller 25 and the weight i5.

While I believe the above described embodlments of my invention to bepreferred embodiments, I wish it to be understood that I do I not desireto be limited to the exact details of .method, design and constructionshown and described, for obvious modifications will occur to a personskilled in the art.

I claim:

1. In looms for weaving, an apparatus for withdrawing a predeterminedlength of weft thread for operating said movable member and adapted -toremove said eye from said opening for a predetermined distance andtothereby pull the weft thread through said opening whereby the weftthread forms a loop the extent of which is in proportion to the lengthof the thread withdrawn from the shed substantially as described.

1 2. In looms for weaving, an apparatus for supplyinga predeterminedlength of weft thread to the shed after completion of the weft insertioncomprising a stationary part adapted to slidin y carry the weft threadand having an opening and a movable member, said movable member havingan eye through which the weft thread runs during the weft insertion intothe shed, said eye being remote from said opening whilethe weft threadisbeing inserted into the shed, a means for operating said movablemember andadapted to move said eye into said opening and. to therebypermit the weft-thread, which formed a loop the size of which is inproportion to the distance of said eye from said opening, to move intothe shed, whereby an additional amount of weft thread is available whichis in proportion to the size of the formerly formed loop, substantiallyas described.

. 3. In a loom for weaving, an apparatus for feeding into-andwithdrawing a predetermined amount of weft thread from the shedcomprising a reciprocable .thread holder having a thread channeltherein, movable jaws carried by said thread holder for gripping thethread protruding from said holder, jaw operating means associated withsaid holder and actuable to close said jaws upon the thread and to opensaid jaws,

and reciprocable means actuating said jaw oper- 'ating means'w hereby,due to the difference of the reciprocating motion of:said thread holderand said reciprocable means, the distance and direction is determined bywhich the thread is carried by the .holder when the jaws are closed.

4. In looms for weaving, an apparatus for withdrawing a predeterminedlength of -weft thread from the shed after completion of the weftinsertion comprising a stationary part .5

adapted to slidingly carry the weft thread and having an opening and amovable member, said movable member having an eye through which the weftthread runs during theweft insertion into the shed, said eye extendinginto said opening while the weft thread is inserted into the shed, amechanism comprising spring means for operating said movable member andadapted to yieldingly remove said eye from said opening and to therebyyieldingly stretch and pull the weft thread through said opening,-whereby the weft thread forms a loop the extent of which is inproportion to the length of the thread withdrawn from the shed,substantially as described.

5. In looms for weaving, an apparatus for supplying a predeterminedlength of weft thread to the shed after completion of the weft insertioncomprising a stationary part adapted to slidingly carrythe, weft threadand having an opening against the action of said means and to therebypermit the weft thread, which formed a loop the size of which is inproportion to the distance of said eye from said opening, to move intothe shed, whereby an additional amount of weft thread is available whichis in proportion to the size of the formerly formed loop, substantiallyas described.

6. In looms for weaving, an apparatus for con trolling the length of theweft thread inserted .into the shed comprising a stationary memberadapted to slidingly carry the weft thread and having an opening, amovable member having an eye through which the weft thread runs duringthe pick, and means for removing said: eye from said opening, wherebytheweft thread is pulled into a loop and withheld from entering the shedand for moving said eye into said opening, whereby weft thread withheldfrom' the shed is permitted to enter the shed.

7. In looms for weaving, an apparatus for controlling the length cf theweft thread inserted into the shed comprising a stationary memberadapted to slidingly carry the weft thread and having an opening, amovable member having an eye through which the weft thread runs duringthe pick, and means for removing said eye from said opening, whereby theweft thread is pulled into a loop and withheld from entering the shedand for moving said eye into said opening, whereby weft thread withheldfrom the shed is permitted to enter the shed, said means comprisingyielding means adapted to yieldingly stretch the weft thread.

8. In a loom for weaving, an apparatus for feeding apredetermined amountof weft thread into the shed and for withdrawing it from the shedcomprising a reciprocable member adapted to slidingly carry the weftthread, movable jaws mounted to said member, jaw operating means movablyconnected with said member and adapted to close said jaws upon thethread and to open said jaws, and actuating means for ac tuating saidjaw operating means.

RUDOLF ROSSMANN.

